This topic describes the ST_ForceRHR function. This function forces the orientation of vertices of a polygon object to follow the Right-Hand-Rule and the area that is bounded by the polygon object is to the right of boundaries.
Syntax
geometry ST_ForceRHR(geometry g);
Parameters
Parameter | Description |
---|---|
g | The geometry object that you want to specify. |
Description
- The exterior rings of the polygon object are orientated in the clockwise direction, and the interior rings of the polygon object are orientated in the anticlockwise direction.
- The ST_ForceRHR function is a synonym for the ST_ForcePolygonCW function.
- This function supports polyhedral surfaces.
- This function supports 3D objects and does not delete z coordinates.
Examples
SELECT ST_AsText(ST_ForceRHR(ST_GeomFromText('POLYGON((1 1,2 1,2 2,1 2,1 1))')));
st_astext
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POLYGON((1 1,1 2,2 2,2 1,1 1))
(1 row)